Did you know that Benadryl and Gravol are the same thing?

My son is barfing all over the place today so I sent my husband to the pharmacy for Gravol. Gravol, however, isn't approved for those under 2 so he asked the pharmacist if there were any other options. He gave my husband baby Benadryl, which he said is the same drug- the only difference is that Benadryl acts faster and makes you sleepier. There is something added to Gravol to try to somewhat counteract the drowsiness, and it is that added ingredient that isn't approved for those under 2.

They're not the same thing! They belong to the same class of medication (first generation antihistamines) but they're different molecules - one is diphenhydramine and the other is dimenhydrinate. Both will help with allergies and nausea, but there's only one ingredient in both products. They may have tweaked the molecule in Gravol to make it less drowsy, but it isn't significant, since it makes most people sleepy.

They're not the same thing! They belong to the same class of medication (first generation antihistamines) but they're different molecules - one is diphenhydramine and the other is dimenhydrinate. Both will help with allergies and nausea, but there's only one ingredient in both products. They may have tweaked the molecule in Gravol to make it less drowsy, but it isn't significant, since it makes most people sleepy.

Really? I Googled it before I posted (because I wanted to be reasonably sure of third-hand information before sharing it with others) and I found this:

Chemically, dimenhydrinate is a salt of two drugs: diphenhydramine and 8-chlorotheophylline, a chlorinated derivative of the theophylline. Theophylline is very closely related to caffeine and theobromine, mild central nervous system stimulants. It was thought that by combining the antiemetic effects of diphenhydramine with a stimulant, the extreme drowsiness induced by the former could be mitigated somewhat by the latter. The sedation caused by diphenhydramine, however, is substantially stronger than the stimulation caused by chlorotheophyllinate, so the overall effect is still mostly sedating.

I took that to mean that dimenhydrinate is made from a combination of diphenhydramine with an added stimulant?

I didn't know that, but it makes sense - most drugs in a class will be very similar chemically, but they're not the same molecule, and sometimes changing one small thing has a huge effect on how it works. It's not the same as a product which is a combination of two things - like a lot of cough and cold products. Some drugs work if one part of the molecule is turned in one way, and if that one part is turned another one it has absolutely no effect. Another example is claritin (loratidine) and aerius (desloratidine), but it's true of many drugs - amoxicillin vs. penicillin etc.